Uwb radar measurement evaluation method and arrangement

Abstract

It is described a method of evaluating radar measurement data, the method comprising: forming plural subsequent channel impulse response profiles (14) from radar signals (6) across subsets of plural subsequent sample time intervals (15), the radar signals (6) being received due to reflection and/or interaction of plural UWB radar radiation pulses (3) transmitted towards a target (4); identifying, in each of the plural channel impulse response profiles (14), one of the plural sample time intervals (15) as a target sample time interval (16) in which received radar signals (6) are comprised originating due to reflection from the target (4); evaluating plural total radar signals of interest (17), each defined as respective magnitude and phase of the plural channel impulse response profiles (14) at the target sample time interval (16), in order to determine for at least one total radar signal of interest a phase (Φ) of a target contribution (21) to the total radar signal of interest (17); determining location and/or movement information of the target (4) based at least on the at least one phase (Φ) of the target contribution (21).

1 . A method of evaluating radar measurement data, the method comprising:
 forming plural subsequent channel impulse response profiles from radar signals across subsets of plural subsequent sample time intervals, the radar signals being received due to reflection and/or interaction of plural UWB radar radiation pulses transmitted towards a target;   identifying, in each of the plural channel impulse response profiles, one of the plural sample time intervals as a target sample time interval in which received radar signals are comprised originating due to reflection from the target;   evaluating plural total radar signals of interest, each defined as respective magnitude and phase of the plural channel impulse response profiles at the target sample time interval, in order to determine for at least one total radar signal of interest a phase of a target contribution to the total radar signal of interest;   determining location and/or movement information of the target based at least on the at least one phase of the target contribution.   
     
     
         2 . The method according to  claim 1 , wherein evaluating the total radar signals of interest comprises:
 determining, for each of the total radar signals of interest, the associated phase of the target contribution to the respective total radar signal of interest, wherein determining the location and/or movement information of the target is based on the phases of the target contribution to all of the respective total radar signals of interest, wherein each channel impulse response profile in particular defines magnitude and phase of the received radar signals for some of the plural sample time intervals.   
     
     
         3 . The method according to  claim 1 , wherein determining the location and/or movement information of the target comprises:
 using the target sample time interval to derive a target location interval and   using at least one phase of the at least one target contribution to estimate movement and/or position of the target within the target location interval.   
     
     
         4 . The method according to  claim 1 , wherein each of the total radar signals of interest comprises:
 a crosstalk contribution, being a contribution due to back coupling and/or crosstalk between a transmitter, transmitting the pulses, and a receiver, receiving the radar signals;   the target contribution, being a contribution due to interaction and/or reflection of the transmitted pulses at the target.   
     
     
         5 . The method according to  claim 1 , wherein evaluating total radar signals of interest comprises:
 determining the crosstalk contribution by processing the plural total radar signals;   subtracting the crosstalk contribution from each of the total radar signals of interest, in order to derive the target contributions, each comprising at least a target phase and in particular a target magnitude.   
     
     
         6 . The method according to  claim 1 ,
 wherein the crosstalk contribution is determined in an approximate manner by averaging the plural total radar signals of interest over an averaging time range,   wherein the approximate crosstalk contribution is subtracted from the total radar signals of interest within the averaging time range, in order to derive approximate target contributions within the averaging time range, each comprising at least an approximate target phase and in particular an approximate target magnitude.   
     
     
         7 . The method according to  claim 1 , wherein determining the crosstalk contribution by processing the plural total radar signals comprises:
 forming cumulative phases of the approximate target phases over different cumulative phase time ranges;   determine a cumulative phase time range of interest, where the cumulative phase of the approximate target phases satisfies a criterium, in particular being substantially or at least 2 Pi or 4 Pi.   
     
     
         8 . The method according to  claim 1 , comprising, if the cumulative phase of the approximate target phases does not satisfy the criterium:
 acquiring further radar measurement data and determining further total radar signals;   determining further cumulative phase time ranges, until a further cumulative phase time range of interest satisfies the criterium.   
     
     
         9 . The method according to  claim 7 , wherein determining the crosstalk contribution further comprises:
 fitting the plural total radar signals of interest across the cumulative phase time interval of interest onto a predetermined curve shape, in particular arc or circle or spiral, the curve shape being associated with a curve center, in particular center of a circle or spiral;   setting the crosstalk contribution to the curve center.   
     
     
         10 . The method according to  claim 1 , wherein if the target phase indicates that target has moved such that its radar signals are received in another target time interval and/or another target sample time interval is identified in the identifying step, the method comprises:
 evaluating other total radar signals of interest, associated with the other target time interval;   determining another crosstalk contribution in the other total radar signals of interest by approximation and/or curve shape fitting;   deriving other target phases;   deriving another target location/movement based on the other target time interval and/or the other target phases.   
     
     
         11 . The method according to  claim 1 , wherein identifying the target sample time interval comprises:
 forming at least one difference between channel impulse response profiles, in particular relative to a reference impulse response profile, and/or forming an average over plural channel impulse response profiles;   performing peak finding in the at least one difference and/or in the average.   
     
     
         12 . The method according to  claim 1 ,
 wherein a channel impulse response profile is formed as an average of received signals in accordance with a code according to which the pulses are transmitted;   wherein forming plural subsequent channel impulse response profiles from the received radar signals comprises at least one of:   removing a carrier radiation contribution;   demodulating the received radar signals, in order to extract in-phase (I) components and quadrature components.   
     
     
         13 . The method according to  claim 1 , wherein at least one of the following holds:
 the target is moving in one direction or is moving back and forth;   the radar signals are received at a rate between 0.5 and 2 GHz, in particular at substantially 1 GHz corresponding to a sample interval width of 30 cm;   a pulse width of the transmitted radar pulses is between 0.5 ns and 2 ns, in particular substantially 1 ns;   the method adhering to IEEE 802.15.4, at least the version corresponding to the priority date of this application.   
     
     
         14 . A method of performing a radar measurement, the method comprising:
 transmitting plural UWB radar radiation pulses towards a target;   receiving, at plural subsequent sample time intervals, radar signals due to reflection and/or interaction of the transmitted pulses at the target;   performing a method of evaluating radar measurement data according to  claim 1 .   
     
     
         15 . An arrangement for evaluating a radar measurement data and in particular performing a radar measurement, the arrangement comprising:
 in particular: a transmitter adapted to transmit plural UWB radar radiation pulses towards a target;   in particular: a receiver adapted to receive, at plural subsequent sample time intervals, radar signals due to reflection and/or interaction of the transmitted pulses at the target;   the arrangement comprising:   a processor adapted:
 to form plural subsequent channel impulse response profiles, across subsets of the sample time intervals, from the received radar signals; 
 to identify, in each of the plural channel impulse response profiles, one of the plural sample time intervals as a target sample time interval in which received radar signals are comprised originating due to reflection from the target; 
 to evaluate total radar signals of interest, each defined as respective magnitude and phase of the plural channel impulse response profiles at the target sample time interval, in order to determine for at least one total radar signal of interest a phase of a target contribution to the total radar signal of interest; 
 to determine location and/or movement information of the target based at least on the at least one phase of the target contribution. 
   
     
     
         16 . The arrangement according to  claim 15 , configured to perform a radar measurement, the arrangement further comprising:
 a transmitter adapted to transmit plural UWB radar radiation pulses towards the target;   a receiver adapted to receive, at the plural subsequent sample time intervals, radar signals due to interaction of the transmitted pulses at the target.   
     
     
         17 . The arrangement according to  claim 15 , wherein each of the total radar signals of interest comprises:
 a crosstalk contribution, being a contribution due to back coupling and/or crosstalk between the transmitter, transmitting the pulses, and the receiver, receiving the radar signals; and   the target contribution, being a contribution due to interaction and/or reflection of the transmitted pulses at the target.   
     
     
         18 . The arrangement according to  claim 17 , wherein the crosstalk contribution is determined in an approximate manner by averaging the plural total radar signals of interest over an averaging time range, and wherein the approximate crosstalk contribution is subtracted from the total radar signals of interest within the averaging time range, in order to derive approximate target contributions within the averaging time range, each comprising at least an approximate target phase and in particular an approximate target magnitude. 
     
     
         19 . The arrangement according to  claim 17 , wherein the processor is further adapted to:
 determine the crosstalk contribution by processing the plural total radar signals; and   subtract the crosstalk contribution from each of the total radar signals of interest, in order to derive the target contributions, each comprising at least a target phase and in particular a target magnitude.   
     
     
         20 . The arrangement according to  claim 17 , wherein the processor is further adapted to:
 form cumulative phases of the approximate target phases over different cumulative phase time ranges; and   determine a cumulative phase time range of interest, where the cumulative phase of the approximate target phases satisfies a criterium, in particular being substantially or at least 2 Pi or 4 Pi.